/*
* low_level_output():
*
* Should do the actual transmission of the packet. The packet is
* contained in the pbuf that is passed to the function. This pbuf
* might be chained.
*
*/
static err_t
low_level_output(struct netif *netif, struct pbuf *p)
{
SYS_ARCH_DECL_PROTECT(lev);
struct xemac_s *xemac = (struct xemac_s *)(netif->state);
xemacliteif_s *xemacliteif = (xemacliteif_s *)(xemac->state);
XEmacLite *instance = xemacliteif->instance;
struct pbuf *q;
SYS_ARCH_PROTECT(lev);
/* check if space is available to send */
if (XEmacLite_TxBufferAvailable(instance) == TRUE) {
if (pq_qlength(xemacliteif->send_q)) { /* send backlog */
_unbuffered_low_level_output(instance, (struct pbuf *)pq_dequeue(xemacliteif->send_q));
} else { /* send current */
_unbuffered_low_level_output(instance, p);
SYS_ARCH_UNPROTECT(lev);
return ERR_OK;
}
}
/* if we cannot send the packet immediately, then make a copy of the whole packet
* into a separate pbuf and store it in send_q. We cannot enqueue the pbuf as is
* since parts of the pbuf may be modified inside lwIP.
*/
q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_POOL);
if (!q) {
#if LINK_STATS
lwip_stats.link.drop++;
#endif
SYS_ARCH_UNPROTECT(lev);
return ERR_MEM;
}
for (q->len = 0; p; p = p->next) {
memcpy(q->payload + q->len, p->payload, p->len);
q->len += p->len;
}
if (pq_enqueue(xemacliteif->send_q, (void *)q) < 0) {
#if LINK_STATS
lwip_stats.link.drop++;
#endif
SYS_ARCH_UNPROTECT(lev);
return ERR_MEM;
}
SYS_ARCH_UNPROTECT(lev);
return ERR_OK;
}
static err_t
low_level_output(struct netif *netif, struct pbuf *p)
{
SYS_ARCH_DECL_PROTECT(lev);
err_t err;
struct xemac_s *xemac = (struct xemac_s *)(netif->state);
xlltemacif_s *xlltemacif = (xlltemacif_s *)(xemac->state);
SYS_ARCH_PROTECT(lev);
/* check if space is available to send */
if (is_tx_space_available(xlltemacif)) {
_unbuffered_low_level_output(xlltemacif, p);
err = ERR_OK;
} else {
#if LINK_STATS
lwip_stats.link.drop++;
#endif
print("pack dropped, no space\r\n");
err = ERR_MEM;
}
SYS_ARCH_UNPROTECT(lev);
return err;
}
static void
xemacif_send_handler(void *arg) {
struct xemac_s *xemac = (struct xemac_s *)(arg);
xemacliteif_s *xemacliteif = (xemacliteif_s *)(xemac->state);
XEmacLite *instance = xemacliteif->instance;
struct xtopology_t *xtopologyp = &xtopology[xemac->topology_index];
XIntc_AckIntr(xtopologyp->intc_baseaddr, 1 << xtopologyp->intc_emac_intr);
if (pq_qlength(xemacliteif->send_q) && (XEmacLite_TxBufferAvailable(instance) == XTRUE)) {
struct pbuf *p = pq_dequeue(xemacliteif->send_q);
_unbuffered_low_level_output(instance, p);
pbuf_free(p);
}
}
static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
SYS_ARCH_DECL_PROTECT(lev);
err_t err;
struct xemac_s *xemac = (struct xemac_s *)(netif->state);
xaxiemacif_s *xaxiemacif = (xaxiemacif_s *)(xemac->state);
/*
* With AXI Ethernet on Zynq, we observed unexplained delays for
* BD Status update. As a result, we are hitting a condition where
* there are no BDs free to transmit packets. So, we have added
* this logic where we look for the status update in a definite
* loop.
*/
XAxiDma_BdRing *txring = XAxiDma_GetTxRing(&xaxiemacif->axidma);
int count = 100;
SYS_ARCH_PROTECT(lev);
while (count) {
/* check if space is available to send */
if (is_tx_space_available(xaxiemacif)) {
_unbuffered_low_level_output(xaxiemacif, p);
err = ERR_OK;
break;
} else {
#if LINK_STATS
lwip_stats.link.drop++;
#endif
process_sent_bds(txring);
count--;
}
}
if (count == 0) {
print("pack dropped, no space\r\n");
err = ERR_MEM;
}
SYS_ARCH_UNPROTECT(lev);
return err;
}
